Eye on the Truth
Abraham was neither a Jew nor a Christian, but he was one inclining toward truth, a Muslim [Monotheist]. And he was not of the polytheists.
Your First Steps in Islam: Belief in the Books of Allah
One must believe that Allah revealed Heavenly Books to His Messengers in order to convey them to mankind. These Books, during their times, contained nothing but the truth. All these Books call people to worship Allah alone, and that He is the Creator, Proprietor and Owner, and to Him belong the beautiful Attributes and Names….